Back in February 2015, a group project was set up at The Whole Half Life (TWHL). Each mapper would be given a set amount of space in order to create a floor in a tower. The gameplay, appearance and story of each floor is unique, decided by the mapper.
After a few months, the final maps were sent to Urby, who linked them together, added a start and end map, and the result was TWHL TOWER!